This invention relates to a tomato harvester characterised by the special configuration of the plant handling devices which eliminates a number of drawbacks present in harvesters designed in accordance with the known state of the art and considerably increases the practicality of the machine. In particular, in the harvester in accordance with the invention, the grid conveyor that discharges the plants stripped of tomatoes onto the ground runs inside the harvester to a point beneath the belt that feeds in the cut plants, following a route that first conveys the plants to shakers that detach the tomatoes from the plants, and then discharges the stripped plants onto the ground.
This configuration eliminates a number of components which can cause soil accumulation and clogging in known harvesters.
The machines used for mechanised tomato harvesting are generally self-propelled and have a cutting blade at the front to cut the plants at ground level and a feed belt that picks up the cut plants and unloads them into the harvester, where shakers detach the tomatoes so that they fall onto a second conveyor belt which leads to collecting containers. The plants are then removed from the harvester by a conveyor belt which receives them at the exit from the shakers and discharges them onto the ground outside the harvester.
For the sake of clarity, one of these harvesters of known type will now be illustrated schematically, by reference to the annexed FIGS. 1 and 2.
The various devices are fitted to a chassis 1 mounted on wheels 2 which are driven by a motor not illustrated in the figure.
The front of the harvester is fitted with a cutting blade 3 mounted on an adjustable-height header 4.
Blade 3 cuts the plants, which fall onto a belt 5, also fitted to header 4; the said belt 5 conveys the plants to a feed belt 6 which unloads the plants bearing the tomatoes into the harvester.
There, the plants fall onto a kind of sloping grid consisting of a set of parallel bars 7, spaced at a sufficient distance apart to allow the tomatoes to fall through the grid, beneath which they are collected by a collector belt 8 that unloads them into collecting containers.
A shaker device 9 of known type is installed in proximity to bars 7. The plants conveyed from sloping bars 7 fall onto a grid conveyor 12 installed beneath the shaker.
All these devices are known, and described, for example, in Italian patent no. 1,278,260 held by the applicant, from which further details can be obtained.
In current harvesters, devices that push the plants forward are fitted immediately below feed belt 6, preventing the said feed belt 6 from dragging them backwards on its return route; in this specific case the device is constituted by a rubber roller 13.
For this purpose a roller 13 made of rubber or other material is fitted immediately beneath feed belt 6, in correspondence with the area in which the said belt unloads the plants bearing the tomatoes.
The roller is kept rotating at a higher speed than belt 6 so as to push the plants towards shaker 9.
The surface of roller 13 presents a number of grooves into which the ends of bars 7 are inserted so that they do not project outwards from the roller surface.
The bars are supported by support arms 14 located immediately downstream of roller 13.
In these known harvesters the plants discharged from belt 6 fall onto bars 7 where they are engaged by rods 10 which pull them forwards as they rotate, and at the same time shake the plants to detach the tomatoes. At the exit from the shaker the plants are discharged outside the harvester by grid conveyor 12, while the tomatoes that fall through the grid are collected by belt 8.
Any plants caught in feed belt 6, which would otherwise tend to drag them backwards, are subject to the action of roller 13, which rotates with a peripheral speed greater than the speed of belt 6 and pushes the plants forward towards shaker 9.
Although this known solution produces good results, it presents a number of drawbacks; in particular, if the soil is wet or damp, it easily adheres to the rubber roller and accumulates in the area between bars 7 and feed belt 6, which soon clogs.